In order to enable an aircraft to take off from an aircraft carrier it is necessary to catapult the aircraft in order to compensate for the very short take-off run. The catapult generally comprises a slug which projects slightly above the take-off deck and which is driven at high speed during catapulting. The motion of the slug is transmitted to the aircraft by a catapult bar which is generally mounted to pivot about a pin carried by the landing gear between a stand-by position in which the catapult bar is in a substantially horizontal position in order to avoid running the risk of it catching on items on the deck while the aircraft is being maneuvered, and a position in which it is lowered towards the deck when the aircraft is ready to be catapulted in order to allow it to engage the catapult slug. The catapult bar is generally also provided with a completely folded-away position in order to reduce the stowage volume of the landing gear when retracted.
In existing systems, the mechanism for controlling the position of the catapult bar generally comprises a multiplicity of springs whose effects compensate one another to a greater or lesser extent depending on the position of a control member associated with the catapult bar. Such devices are not only complex in structure, and therefore heavy, they also suffer from the risk of the counter-balancing springs breaking due to fatigue resulting from the numerous reciprocating forces to which they are subjected.
An object of the present invention is to propose a mechanism for controlling a catapult bar which is both simple and very safe in operation.